Merge commit '0b66e744263a4af1f14d03886ea2a9da4ca156db' into glitch-soc/merge-upstream

app/controllers/api/v1/donation_campaigns_controller.rb

@@ -0,0 +1,86 @@
+# frozen_string_literal: true
+
+class Api::V1::DonationCampaignsController < Api::BaseController
+  before_action :require_user!
+
+  STOPLIGHT_COOL_OFF_TIME = 60
+  STOPLIGHT_FAILURE_THRESHOLD = 10
+
+  def index
+    return head 204 if api_url.blank?
+
+    json = from_cache
+    return render json: json if json.present?
+
+    campaign = fetch_campaign
+    return head 204 if campaign.nil?
+
+    save_to_cache!(campaign)
+
+    render json: campaign
+  end
+
+  private
+
+  def api_url
+    Rails.configuration.x.donation_campaigns.api_url
+  end
+
+  def seed
+    @seed ||= Random.new(current_account.id).rand(100)
+  end
+
+  def from_cache
+    key = Rails.cache.read(request_key, raw: true)
+    return if key.blank?
+
+    campaign = Rails.cache.read("donation_campaign:#{key}", raw: true)
+    Oj.load(campaign) if campaign.present?
+  end
+
+  def save_to_cache!(campaign)
+    return if campaign.blank?
+
+    Rails.cache.write_multi(
+      {
+        request_key => campaign_key(campaign),
+        "donation_campaign:#{campaign_key(campaign)}" => Oj.dump(campaign),
+      },
+      expires_in: 1.hour,
+      raw: true
+    )
+  end
+
+  def fetch_campaign
+    stoplight_wrapper.run do
+      url = Addressable::URI.parse(api_url)
+      url.query_values = { platform: 'web', seed: seed, locale: locale, environment: Rails.configuration.x.donation_campaigns.environment }.compact
+
+      Request.new(:get, url.to_s).perform do |res|
+        return Oj.load(res.body_with_limit, mode: :strict) if res.code == 200
+      end
+    end
+  rescue *Mastodon::HTTP_CONNECTION_ERRORS, Oj::ParseError
+    nil
+  end
+
+  def stoplight_wrapper
+    Stoplight(
+      'donation_campaigns',
+      cool_off_time: STOPLIGHT_COOL_OFF_TIME,
+      threshold: STOPLIGHT_FAILURE_THRESHOLD
+    )
+  end
+
+  def request_key
+    "donation_campaign_request:#{seed}:#{locale}"
+  end
+
+  def campaign_key(campaign)
+    "#{campaign['id']}:#{campaign['locale']}"
+  end
+
+  def locale
+    I18n.locale.to_s
+  end
+end